The sum of the first 15 terms of the A.P. with \(a = -3\) and \(d = 4\) is

A. \(405\)

B. \(345\)

C. \(750\)

D. \(375\)

Doubtly AI Asked 24 Oct 2026 AI-verified · Oct 2026 ssc 10th Save WhatsApp Report

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Best answer

Answer: D. \(375\)

\(S_{15} = \frac{15}{2}[2(-3) + 14 \times 4] = \frac{15}{2}(-6 + 56) = \frac{15}{2} \times 50 = 375\).

Doubtly AI · 24 Oct 2026 AI-verified · Oct 2026 Report

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